Unbalanced factor meter



Dec- 29 1925- K 1,567,582

\ R. D. EVANS ET AL UNBALANCED FAToR METER Filed sept. 16, 1921 ATTORNEYEen. 29,

UN! PATENT CPPECE.

ROBERT ID.` EVANS, F PITTSBURGH, AND RAYT/IOND T. PIERCE, OF\V1LKINSBURG, PENNSYLVANIA, ASSEGNORS TO VESTINGHOJSE ELECTRIC :SiMANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

UNBALANCED FACTOR METER.

Application filed September 1G, 1921. Serial No. 501,078.

To all whom t may concern.'

I B'e 1t known that we, ROBERT D. EVANS, a citizen of the United States,and a resident of Pittsburgh, in the county of Allegheny and State ofPennsylvania, and RAYMOND T. Pinnen, a citizen ofthe United States, anda resident of lfiilkinsburg, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in UnbalancedFactor' Meters, of which the following is a specification.

Our invention relates to measuring devices and systems and it hasspecial relation to measurement of the symmetrical compo! nents orfactors into which an unbalanced quantity of an electrical circuit maybe resolved.

In practicing our invention we utilize the broad principles ofindicating the symmetrical 'components of the unbalanced quantities ofanelectrical system that are disclosed in the co-pending application ofCharles Le Cr. Fortescue, Lewis W. Chubb and Joseph n? Slepian, SerialNo. 358,37 3, tiled February t 13, 1920, Patent No. 1,535,593, grantedApril 2S., 1925, and also in the co-pending application of Chester T.Allcut-t, Serial No. 3Ti),229, filed March 31, 1920, both applicationsbeing assigned to the Testinghouse Electric & Manufacturing Company. y

llt has been discovered that any unbalanced polyphase system ofelectrical quantities, for instance, currents or voltages, may beresolved into two or more symmetrical systems. These quantities, forexample, may be resolved into a positive-phase-sequence component, anegative-phase-se quence component and a Zero-phase-sequence component.In a three-phase, three-wire system the zero-phase-sequence component isof cero value and only the positive and the negative-phase-sequencecomponents need be considered.

In vthe former application, referred to I above, a general method andsystem of apparatus for segregating either of the pliasesequencecomponents of one of the electrical quantities is described and claimed.

In the latter application, referred to '(90 above, is described andclaimed a method `and apparatus for segregating one of the components bystationary resistors and reactors ha'ving predetermined relativecharacteristics,

One object of our invention is to provide an instrument of the Kelvinbalance type en'ibodying the principles set forth above and that isparticularly adapted for use in a graphic type of meter.

More specifically stated, it is the object of our invention to provide aKelvin balance, the respective sets of coils of which are en ergized inaccordance with a positive-phase sequence component and anegative-phasesequence component of the supply-circuit current,together' with means for varying the current in one coil oppositely tothat in the other.

Our invention may best be understood by reference to the accon'ipanyingdra .ving, the single figure of which is a diagrammatic view of ameasuring system organized in accordance with our present invention.

Referring to the drawing, the system here shown comprises a plurality ofsupply-cir cuit conductors 1, 2 and 3, upon which is impressed anunbalanced voltage, or in which an unbalanced load causes an unbalancedcurrent to traverse the circuit. A positivephase-sequence producingsystem fi and a negative-phase-sequence producing system 5 areassociated with the respective sets of coils of a Kelvin balance 6. Aplurality of adjustable resistors 7 and 8 are provided in connectionwith the respective sets of coils, as hereinafter more fully set forth.

The positive-phasesequence network 4 comprises a plurality of secondarywindings 10 and 11 of current transformers that are respectivelyassociated with the supply-circuit conductors 1 and 2 and have a commonmiddle connect-ion. A combined resistor and reactor or reactiveimpedance 12 is connected across the terminals of the secondary winding10 and a resistor 13 of equal absolute value is connected across theterminals of the other secondary winding 11. The arrangement of parts,including the secondary wiudings 10 and 11 and the devices l2 and 13, issuch that a voltage 'proportionai to the positive-phase-seq'uencecomponent of current is produced at the terminals of the network si, inaccordance with the principles set forth in the above-identifiedcopending applications.

With this arrangement, the impedance device 12 has a voltage impressedthereupon, that is proportional to the current-traversing across thedevice 12 under balanced conditions.

The impedance device 12 is of such character that the current traversingthesame lags the impressed voltage by 60, so that the voltage is exactlyin phase under balanced conditions with that impressed across theresistor 13. Accordingly a voltage that is proportional to thepositive-phase-sequence component, is produced vatthe terminals of thenetwork 4.

On the other hand, the negative-phase-sequence system comprises aplurality of secondary windings 14 and 15o'f current transformers Whichyare respectively associated With supply-circuit 'conductors 1 and 3.

yA combined resistor and reactor or reactive impedance I16 is connectedacross the terminals 'of the Secondary Winding 14, While a resistor 17of equal absolute value is'connected across the lterminals of thesecondary Winding 15. Y n

Inthe vpresent instance, the use of the supply-circuit conductor v3 inlieu kof the conductor 2 l that is employed lin 'connection Withthepositive-phase-sequence system 4 so reversesthe phase relations Withinthe system 5 that the voltages across the impedances `ittiand 17 areexactly'opposite inphase underbalance-d conditions and a Vvoltageproportional to the desired negative-sequence componentoftheu'nbalaiic'ed load current 1s produced at the terminal'sof'thenetwork.

`The Kelvin balance v6 of vwell-known general construction, comprising asuitably fulcrumed balancing member "20, upon one end of'ivhich isdisposeda movable/coil 21 that is adapteditooscillatebetween a'pair ofstationary co-ope'rative coils '22 1and23. IAll three coils'are'connectedin 'series relation across vthe terminals of thepositive-phasesequence instrument 4 and, consequently, thecorrespondingv coils of the 'Kelvin balance Y6 are energized inaccordance'with the positive-phase-sequence component "or lfactor of theunbalanced load in the "supply circuit.

The. other end'of the 'balancing lever 2() is f provided withammable'coil24 lwhich cooperates with a pair of'stationarylcoils and 26,'the threecoils being connected m series relation across' the1-terminals of :the

negativephase-sequence device 5.

The last-named'coils, therefore, fare enerf ancelever 20'in theoneor'theother direc-- cientofla'pen'for ffstyilusf33 adapted Yt9 .co-

operate with a chart 34, a pilot motor associated With the balancinglever 20, in a manner to bc set forth7 to eff-ect rotation of a Wormsha-ft 3G upon which is mounted a traveling nut 37. A rod or insulating'bar 37a is suitably attached to t-hetrfaveling'nut 37 and the ends ofthefba'r are provided with suitable pointers or rheostat arms 30 and 31.To control the pilot motor 35, a movable contact member or finger 38 issuitably attached to the coil 21. A plurality of stationary terminals orcontact members 39 and 40 are locatedon opposite sides of the linger '38lto be respectively engaged thereby in the one -orvthe other eXtremeposition of the movable coil.

Co-operating with the contact members 38, 39 and 4() are a Aplurality ofresistors 41 and 42 which are connected through the armature ofthe pilotmotor across a suitable direct current supply circuit comprisingconductors 43 and 44. rlhe terminals of the pilot Amotor field windingare respectively connectedfto the movable .linger 3S and thejunction-point of the resistors .41 yand 42.

Since the illustrated :pilot` motor connections are familiar to thoseskilled in the art, no detailed description thereof or of -the pilotmotor operation vis -deemed necessary.

It will be sutlicient to `state that movement ofthe coil 21 in theupward direction to ef'- fectcontact Withthe terminal 39 producesmovement of the pilot motor inthe one direction, While the opposi-tedirection ofmotor movementis obtained vthrough contactv with the lowerterminal 40. Such energize- Vtion'of the pilot .motor effectsacorresponding degree of movement of thetravelingnut .normal oropen-circuit position, although, of

course, the pen 33 remains in the position to which it was moved untilanother actuation of the Kelvin balance produces further energization ofthe pilot mot-or to actuate the pen in the one or the other direction.

The pointer of arm 30 is thus adapt-ed to move along the resistor 7 togradually inycrease or decrease the amount ofresistance that is shunte'dacross the balance coils 21, 2 2- and 23, 4While the other pointer 31 isadapted to.perform a similar function with respect tothe resistor Sandthe remaining coils 24, 25 and 26. I

. The active value of the resistor 7 Will be decreased inthe event of amovement of the Kelvin balance in the one direction, corre Spending to aCertain vara-tien is the ratio between the posit-ive and thenegative-phasesequenc'e components of the currents travers ing theconductors l, 2 and 3. By reason O the rigid mechanical connection ofthe pointers or arms and 31, the resistance oi the other resistor 8 Willbe increased simultaneously with the decrease of the resistance of theresistor In this Way, the value of the current traversing the coils 2l,22 and 23 will be decreased at the same time that the current traversingthe remaining coils of the balance will be increased, to thus restorethe magnetic balance of the apparatus corresponding to the originalconditions. The stylus 33 is thereby given a corresponding and definitedisplacement, although the balance coils 21 return to the normalcondition, as previously mentioned.

The application of the illustrated apparatus to the graphic vtype ofmeter Will be readily apparent to those skilled in the art. For example,if a roll of paper or record sheet 34 travels adjacent the balance 6,the pen or stylus 33 will be actuated towards the right or to the left,in accordance with the degree and type of unbalance in the supplycircuit. Consequently, the resultant wavy line delineated upon thetraveling paper Will furnish a permanent and continuous record of thedegree of unbalance of the symmetrical components or factors of theunbalanced load conditions in the supply c1rcuit.

lt will be seen that we have thus provided a Kelvin-balance type ofmeter that is particularly adapted for recording, the respectiveelement-s or coils of which are energized in accordance with thepositive-phasese quence and the negative-phase-sequence components ofthe unbalanced load conditions in a supply circuit.

Although we have illustrated and described our invention in connectionwith a three-phase supply circuit only, it will be evident that theprinciples of the invention may be readily applied to other types ofpolyphase circuits.

Consequently, ive do not Wish to be restricted to the specific circuitconnections or arrangements of parts herein set forth, as variousmodiiications thereof may be nia/.le without departing from the spiritand scope ot our invention. lVe desire, therct'ore. that only suchlimitations shall be imposed as are indicated in the appended claims.

ive claim our invention:

Il. A measuring device for a poly ph ase cir cuit comprising uuans 'forproducing diien ent symmetrical components of an unbalanced quantity, abalancing relay and means for applying said components to differentelements of said relay.

2. A measuring device for a polyphase circuit comprising means forproducing` ditierent symmetrical components otl an unbal anced quantity,a Kelvin relay and means for applying said components to opposing coilsot said relay.

3. A measuring device for a polyphase circuit comprising means forproducing a positive-phase-sequence and a negativephase-sequencecomponent of the unbalanced current of said circuit, a balancingrelayand means :tor applying said components to different elements of saidrelay.

il. A measuring device for a polyphase circuit comprising means forproducing a positive-phase-sequence and a negativephase-scquencecomponent of the unbalanced current of said circuit, a Kelvin relay andmeans for applying said components to opposing coils of said relay.

5. A measuring device for a polyphasc unbalanced circuit comprising abalancing relay and means for impressing upon said relay a plurality otcomponents or' the set of symmetrical components into which theunbalanced quantities of the circuit may be resolved, said meanscomprising resistors and reactors to be connected between said circuitand. said relay, and having such characteristics as to segregatepredetermined symmetrical components and impress them upon the relay.

6. A measuring device for a polypliase unbalanced circuit comprising aKelvin balance and means for impressing upon said balance apositive-phasesequence and a negative-phasesequence component of theunbalanced current traversing the circuit, said means comprisingresistance and reactance devices associated with the coils oi. saidbalance and having such characteristics and being so connected to saidcircuit as to produce the desired components.

7. A measuring device for a' polyphase circuit comprising means torproducing diterent symmetrical components of an unbal anced quantity,adialancing relay, means for applying said components to differentelements of Said relay and means for varying the effectiveness of saidelements.

S. A measuring device for a polyphase circuit comprising means Forproducing different symmetrical components ot an unbal anced quantity, aKelvin relay, means Yfor applying said components to opposing coils otsaid relay and means for adjustably shunting said coils.

9. A measuring device Ior a polyphasc circuit comprising means, torproducing diterent symmetri ,al components of an unbalanced quantity, abalancing relay, means tor applying said components to dierent elementsof said relay and means responsive to the relay movements for varyingthe eflectiveness of said elements.

l0. A measuring device for a polyphase circuit comprising means forproducing difiii) feront `syii'imotrical Components of an `unbalancedquantity, a Kelvin relay,v means for applying said components toopposing coils' oi' sai@L relay and means dependent upon the movementsof said relay for -adjustably sliuntiiig said coils.

l1. A'measuring device for va polypliase circuit comprising means forsegregating the symn stric'al compone-'nts of an unbal- 10 anoedquantity of the circuit, a Kelvin balanconiieans for applying saidcon'ipononts co-opposing coils off said balance and moans lsponsive tothemovemonls ofsaid balance to estore the same to its normal position.

I11-testim0n whereof Weillave hereunto' subscribed our names 'this 6thday of September, 1921.

VRoBia'ar D. EVANS.

RAYMoN-D l au PIERCE.

